This circuit was originally designed to measure capacitance with an ICL7107 but can be used with other digital modules. The circuit is from Electronics Now magazine from November 1996.
The circuit in the figure can be used to trigger a triac or even a comparator in a project that...
Suggested by a 90s Electronic Design, this circuit drains only 0.25 mA from its source. Listening...
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...